I'm talking about bands like Slayer, Iron Maiden, as well as more extreme death/black metal bands like Blasphemy, Incantation, Katharsis, Demilich, Demigod, Mayhem.

My brother and one of my friends say bands like these especially black metal and death metal are for teenagers (I'm in my mid 20s btw), but I don't believe there should be age limit for music. As long as you like the music you can listen to it and wear the band shirt. They say things like 666, darkness, death, etc are too immature for my age.

examples of clothes I'm talking about: https://cdn.shopify.com/s/files/1/0795/4257/products/SlayHood8_grande.jpg?v=1488583411 http://deathrune-records.com/wp-content/uploads/2014/02/Katharsis-666-ts.jpg http://deathrune-records.com/wp-content/uploads/2016/09/Blasphemy-new-800x800.jpg https://cdn.shopify.com/s/files/1/1768/6487/products/entrantment-zip-back.jpg?v=1512230602 https://cdn.shopify.com/s/files/1/1768/6487/products/blasphemous-blue-hood-front.jpg?v=1512230515 https://cdn.shopify.com/s/files/1/1768/6487/products/blasphemous-blue-hood-back.jpg?v=1512230515 https://foreverplaguedrecords.com/Portals/0/Hotcakes/Data/products/d3f053d7-d211-412a-918e-d5ab83cfa18a/medium/DSN---Nocturnal-March-TShirt-FPR.JPG

I was gonna post this question on a metal sub but obviously I'd only get biased responses from there and I wanted to specifically hear opinions of more unbiased non-metalhead masculine men with TRP perspective, hence posting it here.